Sensei wa Ore no Mono

A third-year high school student named Tachibana Kyou experiences a shift in his life when a young, inexperienced nurse joins the staff at his all-male school. Hirota Natsu is described as having an innocent, youthful appearance that captivates Kyou, leading him to change his previous carefree attitude. He becomes deeply infatuated with her, believing he has discovered genuine affection. However, their growing connection presents challenges due to the nature of their relationship, which defies conventional boundaries between a teacher and a student.